Quantum-Bayesian Coherence: The No-Nonsense Version

QBism's concession: the Born rule as an empirical, normative addition

what the source states

The paper interprets the Born rule as "a normative rule in addition to usual Dutch-book coherence" and states it "should be seen as an empirical addition to Bayesian reasoning itself" — quantum structure is encoded in relations among an agent's probabilities but is not derived from Bayesian rationality alone.

what we infer

The most first-person-friendly mature framework in quantum foundations, conceding in its flagship technical paper that the quantum part is empirically supplied. This is the physicalist steelman's best exhibit: even the program closest in spirit to Zero Worlds imports, rather than derives, the Born rule.

limitations

• QBism does not attempt to abolish the external world; using its concession against stronger idealisms is an inference, and QBists might contest the framing.